The purpose of this template is to document the Precautionary Approach framework components for Pacific Salmon that Science Branch is responsible for producing. This memo is not meant to provide an assessment of stock status. The template is set up so that:

  • main body = advice/information for managers who need to determine the reference points they are responsible when implementing the PA/FSP
  • appendices = technical information (e.g. additional results) of interest & scientific documentation necessary to reproduce the analysis

1 Summary

Example of key summary information for a given stock
SMU Fraser Pink Salmon
Limit Reference Point (Sgen with CI range)
joint science-FAM advice removal reference: e.g., Umsy; X% Umsy; (insert values with range)
other biological reference points to inform management reference points values which may be useful for determining management reference points (e.g., Smsy, X%Smsy, percentile based values)
next year of re-evaluation (insert year here)
recommended approach if points are NOT re-evaluated within timeframe TBD
reccomended threshold to trigger a rebuilding plan TBD (include measurement units & frequency)

2 Background

Suggest some mostly generic language that can be cut & pasted into each PA/FSP memo re: purpose of memo, what it is/is not. PA components that Science is directly responsible for, jointly responsible for, and provides support to Fisheries Management for.

If helpful, could (generically) include what some biological refpts are (e.g. 80% Smsy, Umsy, etc.) and why they may be considered / informative when determining management reference points

include terminology that we want to use for all PA/FSP memos:

  • biological reference points (which can include WSP biological benchmarks)
  • management reference points
  • Q: Harvest Decision Rule vs Harvest Control Rule??? (have kept as HCRs in this version, can change if that’s the new terminology)
  • etc.

3 Biological Context

  • stock aggregation units/structure - i.e. how does CU, MU & SMU relate for this group?
  • are there any previous estimates of biological reference points? if yes: what are they and when were they estimated?
  • include any relevant ecological info, e.g.:
    • age structure
    • migration, spawn timing
    • distribution
    • etc…incl. any trends

4 Harvest Control Rule

  • description / diagram of current HCR
  • ID any “implied” management values that come from the HCR (will be useful for comparative purposes to biological benchmarks)
  • work with FAM / FAM to provide short summary of ancillary mgmt pieces - e.g., time, area, effort control that works with the HCR
Inferred Fraser pink salmon harvest control rule with estimated Limited Reference Point (S~GEN~; LRP), 80%S~MSY~, and U~MSY~ (medians +/- 95% credible intervals).

Inferred Fraser pink salmon harvest control rule with estimated Limited Reference Point (SGEN; LRP), 80%SMSY, and UMSY (medians +/- 95% credible intervals).

 
 

5 Data summary & plots

  • descriptive plots of data used in analysis to show quantity of data available
  • any description/caveats re: data quality would be useful to include in this section, as well
  • data tables go in appendix
Estimates of Fraser pink salmon spawner abundance, harvest and total returns over time

Estimates of Fraser pink salmon spawner abundance, harvest and total returns over time

 
 
Sampling stanzas and assumed observation error CVs used in state-space spawner-recruitment model
Years Method CV
1957-1985 PSC mark-recapture (system specific) 20%
1987-1991 DFO mark-recapture (system specific) 20%
1993-2001 DFO mark-recapture (mainstem) 20%
2003-2007 Test fishery 50%
2009-2011 Mission post-season 35%
2013-2021 Mission in-season 35%

6 Methods - summary

short, general audience description of methods and how uncertainty was incorporated (or not). Put details that are required for scientific documentation in appendix

7 Results for PA/FSP implementation

focus in this section is on results that determine the reference points that Science Branch is responsible / jointly responsible for and biological reference points that managers may want to consider when making decisions re: implementation of PA/FSP reference points

7.1 Part A: biological reference point values

This will be provided at both SMU & CU level (when they are not a 1:1 relationship)

Table(s) of benchmark values and uncertainty range: for both those that Science is responsible / co-responsible for as well as benchmarks that could help FAM determine management reference points
median lower.CI upper.CI
80% Smsy 4.0835 2.9952 6.2703
Sgen 1.3530 0.7526 2.8344
Umsy 0.5906 0.4668 0.6848
25th percentile 1.9233 NA NA
50th percentile 4.5600 NA NA

7.2 Part B: risk context

things that may be helpful for managers as they determine management reference points. e.g., kobe plots, comparison of biological benchmarks to: historical data (spawners, harvest rates, etc.), harvest control rules, etc.), risk tables/plots/profiles, sensitivity analyses…

Kobe plot of estimated spawner abundance and exploitation rate relative to SMSY (x-axis) and UMSY (y-axis), respectively, over time

 
 

  • Q for group: axes –> currently shows using S/Smsy, but one potential mgmt refpt = 80%Smsy (see lighter dotted line); would color coding help? (e.g. red vs green quadrants)  
Estimated spawner abundance over time (+/- 50% and 95% credible intervals) relative to upper (80% S~MSY~) and lower (S~GEN~) Wild Salmon Policy benchmarks

Estimated spawner abundance over time (+/- 50% and 95% credible intervals) relative to upper (80% SMSY) and lower (SGEN) Wild Salmon Policy benchmarks

 
 
 

Estimated exploitation rate over time (+/- 50% and 95% credible intervals) relative to the exploitation rate expected to maximize harvest over under equilibrium conditions (U~MSY~)

Estimated exploitation rate over time (+/- 50% and 95% credible intervals) relative to the exploitation rate expected to maximize harvest over under equilibrium conditions (UMSY)

 
 

Yield, recruitment, and overfishing probability profiles. (a) Optimal yield profile showing the probability that a given spawner abundance is expected to achieve 70%, 80%, or 90% of maximum sustainable yield (MSY). (b) Optimal recruitment profile showing the probability that a given spawner abundance is expected to achieve 70%, 80%, or 90% of maximum sustainable recruitment (S~MSR~). (c) Overfishing profile, calculated as 1 – P(SY > X% of MSY) at S < S~MSY~ , and 0 at S > S~MSY~ , showing the probability that sustained yield (SY) is reduced to less than a percentage (70%, 80%, or 90%) of MSY given a fixed level of escapement. Historical spawning escapements are shown along x-axis in panel (c)

Yield, recruitment, and overfishing probability profiles. (a) Optimal yield profile showing the probability that a given spawner abundance is expected to achieve 70%, 80%, or 90% of maximum sustainable yield (MSY). (b) Optimal recruitment profile showing the probability that a given spawner abundance is expected to achieve 70%, 80%, or 90% of maximum sustainable recruitment (SMSR). (c) Overfishing profile, calculated as 1 – P(SY > X% of MSY) at S < SMSY , and 0 at S > SMSY , showing the probability that sustained yield (SY) is reduced to less than a percentage (70%, 80%, or 90%) of MSY given a fixed level of escapement. Historical spawning escapements are shown along x-axis in panel (c)

8 Additional Considerations

Are there things that Fisheries Management should consider or should know about the results in this memo when developing management benchmarks?

general things to include in this section:

  • sources of uncertainty
  • time varying considerations
  • changing demographics
  • anticipated climate change impacts
  • changes in habitat (past & future)
  • migration impediments

specific things to include in this section:

  • recommended timeframe for next evaluation of reference points & benchmarks
  • rationale for that timeframe
  • recommendation for what to use if re-evaluation does not take place within the recommended timeframe & why
  • recommendation for what would trigger a rebuilding plan: how many year(s) of what units/metric (individual years vs running average vs …) being below LRP would trigger a rebuilding plan, and rationale for recommendation

Spawner-Recruitment relationship. Error bars and grey band are 95% credible intervals, thick black line is the expected relationship

 
 

Recruitment residuals over time (+/- 50% and 95% credible intervals)

Recruitment residuals over time (+/- 50% and 95% credible intervals)

9 Data Sources and Acknowledgements

Data collection, quality control, management, etc. that the analysis relied upon. Include dates (year) when data set used was received and/or last updated.

10 Appendices

technical information that is not directly needed for management purposes, but provides additional information about the results, is necessary for documentation of the analysis and/or to allow for future reproducibility

  1. data
  2. methods
  3. results that are not included in main body of memo - anticipated that these will mostly be diagnostic in nature?
  4. sources of uncertainty (assuming that it will be removed from main body of document)
  5. references